A variety of towing devices are known for towing disabled vehicles such as passenger cars or trucks. Specialized tow trucks sometimes include an overhead boom from which a sling or cradle attachable to the stalled vehicle depends, and are quite popular commercially. Multi-purpose flat bed trucks, which may be adapted for temporary towing purposes, are also known.
Although sling lifted tow trucks are widely used, attachment of the two bar and sling to the vehicle frame or suspension is a dirty task, and as the lifting point of the disabled vehicle is near its front or rear bumper, damage such as denting or twisting to vehicle components is a frequent occurrence. Such damage has been increasing as more plastic parts and shock-collapsible bumpers have been incorporated into passenger cars.
Those tow trucks which utilize a "wheel lift" apparatus usually attach to the front or rear wheels of the vehicle to be towed. However, such tow trucks carry a much higher portion of the towed vehicle's weight than when the lifting point is adjacent the towed vehicle bumper. Thus, although a wheel-lift two truck (which picks up the vehicle to be towed by its wheel, and in which the lifting point is closer to the center of the towed car as compared with a sling-lifted two truck) provides relatively clean attachment and greatly reduces the chances of damage to the towed vehicle, instability of the towed load in transit during acceleration and deceleration and instability of the towing truck due to longitudinal tire load transfer have been problems.
Examples of different types of towing devices may be seen in the following patents: U.S. Pat. Nos. 4,473,334 to Brown; 3,924,763 to Pigeon; and 3,547,290 to Fratzke et al. A number of problems and complications have been encountered, however, with many prior art towing devices. First, it is obviously desirable to remove disabled vehicles from roadways quickly and efficiently. Many prior art devices, however, require that time-consuming physical work be done by the driver, e.g. in securing the vehicle wheels or in engaging extra attachments. Second, a number of prior art devices do not easily adjust to different tire sizes, flat or missing tires, vehicles of varying widths, vehicles in potholes or against curbs, etc. Third, replacement parts have been expensive. Fourth, damage to the vehicle during both attachment and towing resulting from undesirable forces on the vehicle frame is not unlikely. Finally, because of the complexity of many prior art towing devices, driver training may be lengthy and complicated.
There is thus a need in the art for a versatile towing device which will eliminate the aforementioned problems while providing for ease and efficiency in towing. The apparatus and method of the present invention are addressed to this need, and provide a versatile, fast, and substantially foolproof towing device designed to substantially reduce the time, labor, and risk involved in towing.